Get Tru64/cc to compile. Need to add -ieee so that it doesn't choke on

0.0/0.0.  That option appears to affect the regression test result as well.
The compiler documentation doesn't recommend -O4 for universal use, so
let's stick to the conservative -O (== -O2) by default.

Author: petere

src/template/osf

@@ -1,6 +1,6 @@
 if test "$GCC" != yes ; then
   CC="$CC -std"
-  CFLAGS="-O4 -Olimit 2000"
+  CFLAGS="-O -ieee"
 fi
 
 THREAD_SUPPORT=yes

src/test/regress/expected/float8-fp-exception.out

@@ -11,7 +11,6 @@ float8/i.86-.*-freebsd[234]=float8-small-is-zero
 float8/i.86-.*-openbsd=float8-small-is-zero
 float8/i.86-.*-netbsd=float8-small-is-zero
 float8/.*-qnx=float8-exp-three-digits
-float8/alpha.*-dec-osf.*:cc=float8-fp-exception
 float8/i.86-pc-cygwin=float8-small-is-zero
 horology/.*-aix4=horology-solaris-1947
 horology/.*-aix5=horology-solaris-1947